Determination of the hang-off window for deepwater drilling riser

作者：Ju Shaodong^*; Chang Yuanjiang; Chen Guoming; Chen Liming; Xu Liangbin

来源：Acta Petrolei Sinica, 2012, 33(1): 133-136.

• Current velocity
• Deepwater
• Deepwater drilling riser
• Drilling riser
• Environmental loads
• Extreme weather
• Field operation
• Finite-element models
• Hang-off
• Oceanic conditions
• Operating windows
• Wave direction angle
• Wave heights
• Wave period

The riser hang-off window is an extremum condition of environmental load to allow the riser hang-off operation, which is essential to the field operation. Here we put forward a method to analyze operating windows for soft or hard hang-off modes of the riser, which includes to establish a finite-element model for the riser axial dynamic analysis and to examine riser hang-off windows under different oceanic conditions based on the restraint criterion of riser hang-off operations. Analyses of operating windows of wave height and periods show that the hard hang-off window is jointly affected by the vessel heave movement and wave periods, and it gets narrower when the wave period falls into a range of 10~16 s or 20~24 s. The recommended vessel heading for the hard hang-off mode survival in case of extreme weather should be at a 45° wave direction angle. The soft hang-off window is restricted mainly by the telescopic joint stroke and it keeps approximately identical, independent of the wave direction angle. Analyses of operating windows of wave and oceanic current indicate that the maximum allowable wave height for the riser hang-off operation gets smaller when the oceanic current velocity increases. A comparison of operating windows between the two hang-off modes shows that the soft hang-off mode can significantly expand the riser hang-off operating

• 出版日期2012
• 单位中国石油大学（华东）